Are you running polyurethane bushings anywhere? I dont have a lot of experience choosing the correct shock for your application, but when I had 67 GTO and tried to make it handle well, I went overboard with chassis stiffening and as a result the shock from every little bump transferred to the driver. Having a larger car like a B body and having the goals you are trying to achieve, I would keep it rubber bushed and keep sway bars with rubber bushings. Its not as racey but a bit softer on the tush. It still can be at least predictable. What kind of seats are you running? What size wheel? If its down to tires and shocks as the last two things that you are willing to change, try to air down tires to 30 psi, drive it like you are going to church and see if it makes a difference. If the difference isnt noticable then maybe its time for nice shocks.
$0.02
Im hoping there will be more action on this for you, my two cents is just that.
